Cable erection technique and cable erection coil

ABSTRACT

The present invention concerns a cable erection technique using a plastically deformable coil comprising a metal wire formed in a spiral shape and synthetic resin coated on a surface of the metal wire, wherein said coil is inserted outside around a tensile line drawn between utility poles, the coil is elongated until its plastic deformation for forming a series of cable arrangement spaces inside the spiral, and a cable is extended, added or extracted through the cable arrangement space.

BACKGROUND OF THE INVENTION

The present invention concerns a technique for installing various cablesand a coil to be used in this erection technique and, more particularly,a cable erection technique and a cable erection coil, simplifying thecable erection work and, at the same time, allowing to hold cables in astable state during and after the erection work.

In general, when various cables such as communication cable ortelevision cable or the like are to be erected, a messenger wire is putup as tensile line between utility poles, and metal hangers such ascable hangers are attached one by one to this messenger wire with aninterval of 50 to 60 cm, for hanging cables in parallel.

However, in the cable erection work mentioned above, the operatorcarries a number of metal hangers, and attaches these hangers movingwith an interval of 50 to 60 cm along the longitudinal direction of themessenger wire, and moreover, this hanger attachment operation is donein a height; therefore, such operation has been requiring tremendoustime and labor, and considerably high skill.

Of late years, as a method for simplifying the cable erection work, ithas been proposed to use an elastic chain coil formed into a continuousspiral from synthetic resin base material. When a cable is erected bymeans of chain coil, it is possible to insert the chain coil outside themessenger wire, to elongate this chain coil along the messenger wireand, at the same time, to extend the cable inside the coil and fix as itis. Therefore, the cable erection workability can be improvedremarkably.

However, while the elastic chain coil presents an advantage of simpleerection as mentioned above, on the contrary, when the fastener to themessenger wire is off, or when a part thereof is cut off by an accidentor fire due to the component of synthetic resin, the coil shrinkscausing such a problem that the cable droops. Besides, when the cable iserected by elongating the chain coil, if the coil fixed end comes off,or the elongated non fixed end is released accidentally, the chain cableshrinks to its original length by its elastic flexibility, obliging toresume the cable erection from the beginning and thus deteriorating itsworkability.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a cable erectiontechnique and a cable erection coil, simplifying the cable erection workand, at the same time, allowing to hold cables stable during and afterthe erection work.

The cable erection technique of the present invention to attain theaforementioned object is a cable erection technique using a plasticallydeformable coil comprising a metal wire formed in a spiral shape andsynthetic resin coated on a surface of the metal wire, wherein said coilis inserted outside around a tensile line drawn between utility poles,the coil is elongated until its plastic deformation for forming a seriesof cable arrangement spaces inside the spiral, and a cable is extended,added or extracted through the cable arrangement space.

Thus, a cable can be extended, added or extracted easily through thecable arrangement spaces, as the plastically deformable coil is insertedoutside around the tensile line such as messenger wire drawn betweenutility poles, and the coil is elongated until its plastic deformationfor forming a series of cable arrangement spaces inside the spiral.

Besides, as the aforementioned coil is provide with a property to deformplastically when it is elongated, it is possible to prevent the cablefrom drooping based on the resistance of plastically deformed coil, evenif a coil fastener to the messenger wire is off, or a part thereof iscut off by accident or the like, and the cable can be kept stable for along time. Besides, the cable does not shrink to its original lengtheven if the coil fixed end comes off, or the elongated non fixed end isreleased accidentally during the cable erection work; so the cableerection work can be executed efficiently. Moreover, as theaforementioned is provided with metal wire, it can not be cut off byfire.

In the present invention, it is preferable to attach a coil extensiondevice, having a reducing aperture smaller than the outer diameter ofthe coil, to the coil after having inserted the coil outside around thetensile line, and to elongate the coil until it deforms plastically allthe way discharging the coil from the reducing aperture. The use of acoil extension device provided with such reducing aperture allows toimprove the operation efficiency of the aforementioned cable erectiontechnique and, at the same time, to set with good precision the coilsize during the elongation.

To be more specific, it is preferable to insert the coil outside aroundthe tensile line, then engage one end side of the coil to the tensileline, dispose a coil extension device having a reducing aperture smallerthan the outer diameter of the coil at the one end side of the coil,draw the coil extension device to the other end side of the coil alongthe tensile line, and elongate the coil until it deforms plastically allthe way discharging the coil from the reducing aperture. Otherwise, itis preferable to insert the coil outside around the tensile line, thenengage one end side of the coil to the tensile line, dispose a coilextension device having a reducing aperture smaller than the outerdiameter of the coil at the other end side of the coil, draw the otherend side of the coil along the tensile line while fixing the position ofthe coil extension device, and elongate the coil until it deformsplastically all the way discharging the coil from the reducing aperture.

As tensile line for guiding the aforementioned coil, messenger wire madeof a plurality of twisted steel wires, existing cable, complex cableintegrating messenger wire and cable (so-called SS type cable) or otherscan be selected and, if necessary, it can be a temporary rope, or thelike.

However, the cable erection technique of the present invention can alsobe applied to the case without tensile line installation. In this case,using a plastically deformable coil comprising a metal wire formed in aspiral shape and synthetic resin coated on a surface of the metal wire,the coil is elongated until its plastic deformation for forming a seriesof cable arrangement spaces inside the spiral, and a cable is extended,added or extracted through the cable arrangement spaces. Such cableerection technique is preferable for receiving the cable in theroof-space or under the floor arranging the cable.

In the present invention, cables to be extended, added or extractedinclude various cables made of a number of buried electric wires,optical wires or the like, such as communication cable, televisioncable, power transmission cable, or the like and, additionally, servicewire and lead-in wire to the office, dwelling or others.

On the other hand, the cable erection coil of the present invention hasa structure wherein a resin coated wire comprising a metal wire andsynthetic resin coated on a surface of the metal wire is formed in aspiral shape, and is characterized by that said metal wire causespermanent deformation when the coil made of the resin coated wire iselongated.

It is preferable that said metal wire causes permanent deformation whenthe coil is elongated at least 10 times longer than the non-elongatedlength thereof. It is preferable the ratio of the cross-section of themetal wire to the cross-section of the resin coated wire is equal orsuperior to 25%.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an example of plastically deformable coil used for thecable erection technique of the present invention; FIG. 1(a) is a sideview of the coil, FIG. 1(b) a cross-section of a resin coated wirecomposing the coil, and FIG. 1(c) a side view of the resin coated wire.

FIG. 2 shows an example of the coil extension device used for the cableerection technique of the present invention; FIG. 2(a) is a side-view ofnon-elongated coil, and FIG. 2(b) a side-view of elongated coil.

FIG. 3 shows another coil extension device used for the cable erectiontechnique of the present invention; FIG. 3(a) is a side-view ofnon-elongated coil, and FIG. 3(b) a side-view of elongated coil.

FIG. 4 shows a sate of cable erection by the cable erection technique ofthe present invention; FIG. 4(a) shows a side-view, and FIG. 4(b) a viewalong the line X—X.

FIG. 5 shows another sate of cable erection by the cable erectiontechnique of the present invention; FIG. 5(a) shows a side-view, andFIG. 5(b) a view along the line X′—X′.

FIG. 6 shows a cable support structure wherein another cable erectiontechnique of the present invention is applied; FIG. 6(a) shows aside-view, and FIG. 6(b) a view along the line Y—Y.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Now, the present invention will be described in detail referring toattached drawings.

FIG. 1 shows an example of plastically deformable coil used for thecable erection technique of the present invention. As shown in FIG. 1(a)to FIG. 1(c), a plastically deformable coil 1 has a structure wherein aresin coated wire 1A made by coating around a metal wire 1 a withsynthetic resin 1 b is formed in a spiral shape. The cross-section shapeof the resin coated wire 1A is preferably non-circular, includingpolygons such a octagon or others. When the resin coated wire 1A istwisted so as to rotate the non-circular shape spirally in thelongitudinal direction of the metal wire 1 a, the wind sound generatedduring the cable erection may be reduced. The coil 1 has a length L inthe non-elongated state without load before used for the cable erectiontechnique, however, it will have a state elongated to a lengthcorresponding to one span between electric utility poles during thecable erection. When the elongated coil is short or too long for onespan between electric utility poles, the coil 1 may be cut off orprolonged.

The coil 1 mentioned above is provided with such property that the metalwire 1 a deforms plastically, when the coil is elongated from itsnon-elongated length L. To be more specific, when the coil is elongatedby 10 times or more than its non-elongated length L, the coil 1 shrinksfrom the diameter D and, at the same time, it deforms plastically sothat the length after elongation will be kept. If this metal wire ladeforms at an elongation less than 10 times of its non-elongated lengthL, it becomes difficult to elongate the coil 1 so as to keep the spiralpitch at constant interval.

To provide the aforementioned coil 1 made of complex material of themetal wire 1 a and the synthetic resin 1 b with said property, thematerial of the metal wire 1 a and the synthetic resin 1 b may beselected properly and the cross-section ration of the metal wire 1 a atthe resin coated wire 1A may be set properly.

As the metal wire 1 a, iron wire, copper wire, aluminum wire or the likeof 1.0 to 5.0 mm in diameter can be used. Especially, it is preferableto used iron wire to provide the most appropriate plastic deformationfor cable erection. Besides, it is advantageous to use galvanized wireto prevent from corrosion. If the diameter of the metal wire 1 a is lessthan 1.0 mm, its capability to hold the cable becomes insufficient and,on the contrary, if it is more than 5.0 mm, the coil itself becomesheavy unfavorably.

It is preferable to set the ratio of the cross-section of the metal wireto the cross-section of the resin coated wire is equal or superior to25%. If the ratio of the cross-section of the metal wire is less than25%, elastic deformation of the synthetic resin 1 b makes plasticdeformation of the metal wire 1 a difficult. Note that the cross-sectionshape of the metal wire 1 a is not specially limited and, in addition tothe circle as shown in the drawing, it can take oval, triangular,square, octagonal or other polygonal shape.

On the other hand, as synthetic resin 1 b, thermoplastic resin such aspolyester, polyamide, polyolefin can be used. Among these thermoplasticresins, polyester is especially preferable. As this polyester,polyethylene terephthalate, polybutylene terephthalate, or copolymerpolyester obtained by copolymerization of them with a third componentsuch as adipic acid, isophthalic acid, isophthalic sulfonate andpolyethylene glycol can be cited.

Moreover, as polyamide, nylon 6, nylon 66, nylon 610, nylon 612, nylon11, nylon 12 and copolymer polyamide made by combination of componentsof respective nylon can be cited.

Obviously, these thermoplastic resins may comprise as desired heatresistant agent, weather resistant agent, photoresistant agent,antioxidant, antistatic additive, smoother, dye or other normal additivecomponents as necessary.

The non-elongated length L of the coil 1 is preferably short from theviewpoint of handling; however, its workability will be favored if it isset to elongate at least up to 1 span between utility poles during cableerection. For this effect, when the non-elongated length L is within therange of 500 to 2000 mm, the elongated length is preferably set a rangeof 10 to 80 times, especially 20 to 60 times of that length L. Moreover,the outer diameter D of the non-elongated coil 1 is advantageously setto a range of 20 to 120 mm.

Now, the cable erection technique of the present invention will bedescribed. A coil extension device shown in FIG. 2 or FIG. 3 can be usedto extend the aforementioned coil 1.

In FIG. 2, a coil extension device 10 has a structure made by assemblinga bone member 11 in a cone shape, and is provided with a reducingaperture 12 smaller than the outer diameter of the coil 1 at the apex ofthe cone. Moreover, the coil extension device 10 is made of two membersdivided a long the cone slant, and these both members can open or closeby means of a hinge 13 and, moreover, can be cramped in closed state bymeans of a bolt 14.

When the coil 1 is extended by the aforementioned coil extension device10, as shown in FIG. 2(a), first the coil 1 is inserted outside around amessenger wire W drawn between utility poles P, P, then one end side ofthe coil 1 is attached to the messenger wire W with a cram member 2,then the coil extension device 10 provided with the reducing aperture 12smaller than the outer diameter of the coil 1 is disposed at hteone endside of the coil 1. To be more specific, the reducing aperture 12 ispositioned at the one end side of the coil 1 and the coil extensiondevice 10 is installed so that the cone section of the bone member 11covers the coil 1. Then, as shown in FIG. 2(b), the coil extensiondevice 10 is pulled toward the other end side of the coil 1 along themessenger wire W, by means of a traction wire 15 attached to the conebottom of the bone member 11 , and the coil 1 is elongated until itsplastic deformation all the way being discharged from the reducingaperture 12. In order to operate from the ground the coil extensiondevice 10 moving along the messenger wire W, a hook 16 is hung on themessenger wire W, and a ground operation rope 17 is attached to thishook 16. It is also advantageous to attach the other end side of thecoil 1 to the hook 16.

When the coil 1 is extended using the coil extension device 10 asmentioned above, the pitch and the outside diameter of the elongatedcoil 1 can be set based on the size of the reducing aperture 12 and,moreover, the coil 1 can be extended evenly along its total length. Asthe coil extension device 10 is assembled of the bone member 11, thecoil 1 can be handled easily through its gap, and moreover, as it islight, it will not apply much load to the messenger wire W.

On the other hand, in FIG. 3, a coil extension device 20 has a structuremade by assembling a bone member 21 in a cone shape, and is providedwith a reducing aperture 22 smaller than the outer diameter of the coil1 at the apex of the cone. Moreover, the coil extension device 20 ismade of two members divided along the cone slant, and these both memberscan open or close by means of a hinge 23 and, moreover, can be crampedin closed state by means of a bolt 24.

When the coil 1 is extended by the aforementioned coil extension device20, as shown in FIG. 3(a), first the coil 1 is inserted outside around amessenger wire W drawn between utility poles P, P, then one end side ofthe coil 1 is attached to the messenger wire W with a cramp member 2,then the coil extension device 20 provided with the reducing aperture 22smaller than the outer diameter of the coil 1 is disposed at the otherend side of the coil 1. To be more specific, the reducing aperture 22 ispositioned at the other end side of the coil 1 and the coil extensiondevice 20 is installed so that the cone section of the bone member 21covers the coil 1.

Then, as shown in FIG. 3(b), the other end side of the coil 1 isconnected to a leading chariot 26 running freely over the messenger wireW, then the other end side of the coil 1 is drawn by the leading chariot26 along the messenger wire W, with the position of the coil extensiondevice 20 fixed with respect to the utility pole P using a fixing rope25 attached to the cone bottom of the bone member 21, and the coil 1 iselongated until its plastic deformation all the way being dischargedfrom the reducing aperture 22. This leading chariot 26 permits only theadvance, and a brake acts during the regression. In order to operatefrom the ground the leading chariot 26 moving along the messenger wireW, a ground operation rope 27 is attached to the leading chariot 26.Note that such leading chariot 26 may also be applied to the erectiontechnique shown in FIG. 2.

When the coil 1 is extended using the coil extension device 20 asmentioned above, the pitch and the outside diameter of the elongatedcoil 1 can be set based on the size of the reducing aperture 22 and,moreover, the coil 1 can be extended evenly along the total length. Asthe coil extension device 20 is assembled of the bone member 21, thecoil 1 can be handled easily through its gap, and moreover, as it islight, it will not apply much load to the messenger wire W. In addition,if the tip of the cable C is connected to the leading chariot 26, thecable C can be extended at the same time as the extension of the coil 1.

FIG. 4 shows a sate of cable erection by the cable erection technique ofthe present invention. As shown in FIG. 4(a) and FIG. 4(b), according tothe cable erection technique of the present invention, using aplastically deformable coil 1, the coil 1 is inserted outside around themessenger wire W drawn between utility poles, the coil is elongateduntil its plastic deformation for forming a series of cable arrangementspaces S inside the spiral, and a cable C is extended, added orextracted through this cable arrangement space S.

In the cable erection work using the aforementioned coil 1, allsuspension points for hanging the cable C through a helical loop with aconstant interval can be formed, and the cable C can be extended by onlyone operation of simply elongating the coil 1 between utility poles and,moreover, once the cable C is extended, the coil 1 can be used as cablefixing hanger as it is. Consequently, it makes unnecessary to erecttemporarily the cable C by means of a cable extension jig such aspulley, and simplifies the operation to attach a number of metal hangersone by one at a constant interval as in the conventional cable erection.

When the cable C hung from the messenger wire W is to be added, thecable C can be inserted simply from the utility pole side along a seriesof cable arrangement spaces S. Besides, when the number of cables C hungon the messenger cable W is to be reduced, any number of cable(s) C maybe extracted from the cable arrangement spaces S. As the cable C is hungby the plastically deformed coil 1, the cable C does not droop extremelyduring the extraction.

Moreover, as the metal wire 1 a deforms plastically when the coil 1 iselongated, the plastically deformed metal cable la prevents the cable Cfrom drooping, even if a coil fastener to the messenger wire W is off,or a part the coil 1 is cut off by accident or the like. Besides, thecable does not shrink to its original length even if the coil 1 fixedend comes off, or the elongated non fixed end is released accidentallyduring the cable erection work. Therefore, the cable erection techniqueusing the aforementioned coil 1 allows to hold the cable C in a stablestate during and after the erection. Moreover, even if a fire breaks outin the vicinity of the cable erection emplacement, causing the cable 1inflamed and the synthetic resin 1 b burned out, the cable C can be heldby the metal wire 1 a.

FIG. 5 shows another sate of cable erection by the cable erectiontechnique of the present invention. In this embodiment, a SS type cablemade by integrating a messenger wire W′ and a cable C′ through a numberof joints J arranged longitudinally with a predetermined interval isused as tensile line. As shown in FIG. 5(a) and FIG. 5(b), when the SStype cable is used as tensile line, the coil 1 is inserted outsidearound the SS type cable drawn between utility poles, the coil iselongated until its plastic deformation for forming a series of cablearrangement spaces S inside the spiral, and a cable C is extended, addedor extracted through these cable arrangement spaces S.

FIG. 6 shows a cable erection technique by another embodiment of thepresent invention. This embodiment concerns a cable erection techniquefor installing cable in a roof-space without using tensile line. In FIG.6(a) and FIG. 6(b), a pair of right and left stays 31, 31 are hung witha predetermined interval from a top wall surface 30 to the roof-spaceand a support plate 32 is attached to the lower end thereof. A number ofcables C are mounted on this support plate 32.

Since the number of cable C to be mounted on the support plate 32 beinglimited, conventionally, another support plate has been installed nextto the support plate 32 when it is desired to install cables more thanthis limit. However, it requires much labor to install another supportplate. So, it is preferable to apply the cable erection technique of thepresent invention to such a cable support structure too.

Namely, the aforementioned coil 1 is elongated until its plasticdeformation for forming a series of cable arrangement spaces S insidethe spiral and attached to the stay 31, 31 along the support plate 32,and the cable C is extended, added or extracted through the cablearrangement space S.

As such coil 1 elongated to its plastic deformation keeps its shape to acertain degree, it is effective as support structure of the cable C.Moreover, the cable C can be extended, added or extracted easily throughthe cable arrangement space S and, besides, the cable C can be keptstable during and after the erection work.

The cable erection technique of the present invention described abovecan be applied to the erection of various cables such as communicationcable, television cable, power transmission cable, or the like.

Other than the use method mentioned above, the cable erection techniqueof the present invention is also preferable for installing cable insidethe underground passage, common drain, culvert or the like. In theseunderground passage, common drain, culvert or the like, the coil may beelongated along a tensile line such as messenger wire or the like, orthe coil may well be elongated without using a tensile line.

As described above, according to the present invention, using aplastically deformable coil comprising a metal wire formed in a spiralshape and synthetic resin coated on a surface of the metal wire, thecoil is inserted outside around the tensile line drawn between utilitypoles, the coil is elongated until its plastic deformation for forming aseries of cable arrangement spaces inside the spiral, and a cable isextended, added or extracted through the cable arrangement space.Therefore, cable erection workability can be improved remarkably and,moreover, the cable can be held in a stable condition during and afterthe erection work.

What is claimed is:
 1. A cable erection method carried out by using aplastically deformable coil comprising a metal wire formed in a spiralshape and synthetic resin coated on a surface of the metal wire andhaving an original non-elongated length defining a non-elongated state,wherein after said coil in a the non-elongated state having saidoriginal non-elongated length is disposed outside of and around atensile line drawn between utility poles, the coil is elongated untilits plastic deformation for forming a serial space for arranging cablesinside the spiral, and a cable is extended, added or extracted throughthe space.
 2. The A cable erection method according to claim 1 carriedout by using a plastically deformable coil comprising a metal wireformed in a spiral shape and synthetic resin coated on a surface of themetal wire and having an original non-elongated state is disposedoutside of and around a tensile line drawn between utility poles, thecoil is elongated until its plastic deformation for forming a serialspace for arranging cables inside the spiral, and a cable is extended,added or extracted through the space and wherein when said coil isdisposed outside of and around said tensile line, then a coil extensiondevice having a reducing aperture smaller than an outer diameter of thecoil is attached to said coil, and the coil is elongated until itsplastic deformation while being discharged from said reducing aperture.3. The cable erection method according to claim 2, wherein when saidcoil is disposed outside of and around said tensile line, then one endside of the coil is attached to said tensile line, the coil extensiondevice having the reducing aperture smaller than the outer diameter ofthe coil is disposed at said one end side of the coil, said coilextension device is drawn to the other end side of the coil along saidtensile line, and the coil is elongated until its plastic deformationbeing discharged from said reducing aperture.
 4. The cable erectionmethod according to claim 2, wherein when said coil is disposed outsideof and around said tensile line, then one end side of the coil isattached to said tensile line, the coil extension device having thereducing aperture smaller than the outer diameter of the coil isdisposed at the other end side of the coil, the other end side of thecoil is drawn along said tensile line with the coil extension deviceheld at a fixed position, and the coil is elongated until its plasticdeformation while being discharged from said reducing aperture.
 5. Acable erection method according to any of one claims 1 to 4, wherein alength of the elongated coil is set in a range of 10 times to 80 timesof a length L of the non-elongated coil.
 6. A cable erection methodaccording to claim 5, wherein the length L of the non-elongated coil isset in a range of 500 mm to 2000 mm.
 7. A method for erecting a cablebetween spaced-apart support structures with a tensile line drawnbetween the support structures using a plastically deformable coilinitially having a non-elongated state and operative to elongate to anelongated state, the method comprising the steps of: disposing theplastically deformable coil in the non-elongated state outside of andaround the tensile line and adjacent to a selected one of the supportstructures; connecting an end portion of the plastically deformablecoil, which is disposed nearest to the selected one of the supportstructures, to the tensile line; moving a far end portion of theplastically deformable coil, which is disposed opposite to the connectedend portion and farthest from the selected one of the support structuresrelative to the connected end portion, across the tensile line to aremaining one of the support structures causing the plasticallydeformable coil to elongate from the non-elongated state to theelongated state to form a spiral defining a space within which thetensile line is disposed; connecting the far end portion of theplastically deformable coil in the elongated state to the tensile lineadjacent the remaining support structure; and extending the cablebetween the support structures and through the space thereby erectingthe cable between the support structures.
 8. A method according to claim7, wherein the plastically deformable coil is elongated until plasticdeformation occurs thereby preventing the plastically deformable coil toreturn to the non-elongated state.